Martijn. G. Slieker
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Martijn. G. Slieker has a total of 132 co-authors. Here are the top co-authors by number of shared publications:
- Deogratias Nkya
Department of Pediatrics, Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam, Tanzania
4 shared publications - Diederick E. Grobbee
Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
4 shared publications - Johannes M. P. J. Breur
Department of Pediatric Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
4 shared publications - Mohamed Janabi
Jakaya Kikwete Cardiac Institute
4 shared publications - Naizihijwa Majani
Department of Clinical Audit and Quality Assurance, Jakaya Kikwete Cardiac Institute
4 shared publications - Pilly Chillo
Department of Internal Medicine, Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam, Tanzania
4 shared publications
Latest Publications
- Open Access
- 29 September 2025
- Published by Taylor & Francis in Fatigue: Biomedicine, Health & Behavior
- Vol. 14 (1) , 1-14
Fatigue in pediatric congenital heart disease: integrative insight into cardiology-focused, lifestyle, psychological and social factors
- 29 September 2025
- Published by Taylor & Francis in Fatigue: Biomedicine, Health & Behavior
- Vol. 14 (1) , 1-14
Open AccessFatigue in pediatric congenital heart disease: integrative insight into cardiology-focused, lifestyle, psychological and social factors
- Open Access
- 22 September 2025
- Published by Elsevier in Early Human Development
- Vol. 211, 106397
Associations between cardiorespiratory fitness, activity behavior, physical literacy and parental sports participation in children with a critical congenital heart disease
- 22 September 2025
- Published by Elsevier in Early Human Development
- Vol. 211, 106397
Open AccessAssociations between cardiorespiratory fitness, activity behavior, physical literacy and parental sports participation in children with a critical congenital heart disease
- Open Access
- 22 August 2025
- Published by MDPI AG in Journal of Cardiovascular Development and Disease
- Vol. 12 (9) , 322
Right Ventricular Strain in Healthy Children: Insights from Speckle-Tracking Echocardiography
Background: Right ventricular (RV) strain using two-dimensional speckle tracking is a reliable and clinically significant tool for detecting RV systolic dysfunction, but it varies by age, vendor, and software. Objectives: To establish pediatric age-specific normal values and Z-score equations for biventricular strain using GE Healthcare equipment and software. Methods: Children 0–18 years with structurally and functionally normal hearts, who visited the Wilhelmina Children’s Hospital Utrecht between October 2020 and December 2023, were retrospectively included and divided into age groups: 0 years, 1–4 years, 5–9 years, 10–13 years, and 14–18 years. Left ventricular (LV) and RV global longitudinal strain (GLS) and RV free wall longitudinal strain (FWGLS) were analyzed. Results: We included 129 subjects (57% male) (0 years: n = 17; 1–4 years: n = 22; 5–9 years: n = 34; 10–13 years: n = 35; 14–18 years: n = 20). Low R2 values were strain-adjusted for age, height, and body surface area (all < 0.3), and the sample size limited Z-score equation reliability. Therefore, data are presented as mean ± SD or median [IQR] stratified by age. LV GLS, RV GLS, and RV FWGLS showed a nonlinear relationship with age, peaking at the 1–4 years age group and decreasing with age. Conclusions: LV GLS, RV GLS, and RV FWGLS showed age-related differences in children using GE equipment and software, which highlights the importance of age-specific normal strain values, including Z-score equations as a function of age.
- 22 August 2025
- Published by MDPI AG in Journal of Cardiovascular Development and Disease
- Vol. 12 (9) , 322
Open AccessRight Ventricular Strain in Healthy Children: Insights from Speckle-Tracking Echocardiography
Background: Right ventricular (RV) strain using two-dimensional speckle tracking is a reliable and clinically significant tool for detecting RV systolic dysfunction, but it varies by age, vendor, and software. Objectives: To establish pediatric age-specific normal values and Z-score equations for biventricular strain using GE Healthcare equipment and software. Methods: Children 0–18 years with structurally and functionally normal hearts, who visited the Wilhelmina Children’s Hospital Utrecht between October 2020 and December 2023, were retrospectively included and divided into age groups: 0 years, 1–4 years, 5–9 years, 10–13 years, and 14–18 years. Left ventricular (LV) and RV global longitudinal strain (GLS) and RV free wall longitudinal strain (FWGLS) were analyzed. Results: We included 129 subjects (57% male) (0 years: n = 17; 1–4 years: n = 22; 5–9 years: n = 34; 10–13 years: n = 35; 14–18 years: n = 20). Low R2 values were strain-adjusted for age, height, and body surface area (all < 0.3), and the sample size limited Z-score equation reliability. Therefore, data are presented as mean ± SD or median [IQR] stratified by age. LV GLS, RV GLS, and RV FWGLS showed a nonlinear relationship with age, peaking at the 1–4 years age group and decreasing with age. Conclusions: LV GLS, RV GLS, and RV FWGLS showed age-related differences in children using GE equipment and software, which highlights the importance of age-specific normal strain values, including Z-score equations as a function of age.
- Open Access
- 1 July 2025
- Published by Springer Nature in Scientific Reports
- Vol. 15 (1) , 1-7
Translation and validation of the Swahili pediatric quality of life family impact module for caregivers of children with congenital heart disease
The Pediatric Quality of Life Inventory™ (PedsQL™) family impact module is a widely used tool for assessing the health-related quality of life (HRQoL) of caregivers of children with chronic illnesses; however, it has not been available in Swahili. This study aimed to translate, culturally adapt, and validate the Swahili version of the PedsQL family impact module (FIM) among caregivers of children with heart disease in Tanzania. As a secondary aim, the study explored differences in caregiver HRQoL between those whose children had undergone surgery and those who had not, using the newly translated tool. A cross-sectional survey was conducted among 204 primary caregivers at a national cardiac referral centre. Standardised translation and adaptation procedures were followed. Psychometric evaluation included internal consistency reliability, construct validity through known-groups comparisons, and effect size estimation. The Swahili version demonstrated excellent internal consistency (Cronbach’s α = 0.99) and good construct validity. Socioeconomic status was the only consistent predictor of HRQoL in multivariable models. Caregivers in the operated group consistently reported higher HRQoL scores, highlighting the potential benefit of surgical intervention on family well-being. These findings strongly support the Swahili PedsQL FIM as a culturally appropriate and psychometrically sound tool. It offers promise for clinical care and future outcome evaluations in similar settings.
- 1 July 2025
- Published by Springer Nature in Scientific Reports
- Vol. 15 (1) , 1-7
Open AccessTranslation and validation of the Swahili pediatric quality of life family impact module for caregivers of children with congenital heart disease
The Pediatric Quality of Life Inventory™ (PedsQL™) family impact module is a widely used tool for assessing the health-related quality of life (HRQoL) of caregivers of children with chronic illnesses; however, it has not been available in Swahili. This study aimed to translate, culturally adapt, and validate the Swahili version of the PedsQL family impact module (FIM) among caregivers of children with heart disease in Tanzania. As a secondary aim, the study explored differences in caregiver HRQoL between those whose children had undergone surgery and those who had not, using the newly translated tool. A cross-sectional survey was conducted among 204 primary caregivers at a national cardiac referral centre. Standardised translation and adaptation procedures were followed. Psychometric evaluation included internal consistency reliability, construct validity through known-groups comparisons, and effect size estimation. The Swahili version demonstrated excellent internal consistency (Cronbach’s α = 0.99) and good construct validity. Socioeconomic status was the only consistent predictor of HRQoL in multivariable models. Caregivers in the operated group consistently reported higher HRQoL scores, highlighting the potential benefit of surgical intervention on family well-being. These findings strongly support the Swahili PedsQL FIM as a culturally appropriate and psychometrically sound tool. It offers promise for clinical care and future outcome evaluations in similar settings.
- Open Access
- 6 May 2025
- Published by Elsevier in Annals of Oncology
- Vol. 36 (9) , 1025-1034
Long-term development of 12- and 15-year-old offspring after maternal cancer diagnosis during pregnancy: a prospective multicentre cohort study
- 6 May 2025
- Published by Elsevier in Annals of Oncology
- Vol. 36 (9) , 1025-1034
Open AccessLong-term development of 12- and 15-year-old offspring after maternal cancer diagnosis during pregnancy: a prospective multicentre cohort study
- Open Access
- 4 November 2024
- Published by Wolters Kluwer Health in Journal of the American Heart Association
- Vol. 13 (21) , e036208
Clinical Features and Outcomes of Pediatric MYH7 ‐Related Dilated Cardiomyopathy
Background: Although genetic variants in MYH7 are the most frequent cause of pediatric genetic dilated cardiomyopathy (DCM), there are no studies available describing this entity. We sought to describe clinical features, analyze variant location, and explore predictors of bad prognosis in pediatric MYH7 ‐related DCM. Methods and Results: We evaluated clinical records from 44 patients (24 men; median age at diagnosis, 0.54 [interquartile range, 0.01–10.8] years) with pathogenic/likely pathogenic variants in MYH7 diagnosed with DCM at pediatric age (P =0.002) and LV ejection fraction ≤35% (HR, 4.00 [95% CI, 1.11–14.4]; P =0.03) were the best predictors of bad prognosis. Conclusions: Pediatric MYH7 ‐related DCM is characterized by early onset, frequent LV hypertrabeculation, and poor prognosis. Advanced New York Heart Association class and low LV ejection fraction emerged as predictors of end‐stage heart failure.
- 4 November 2024
- Published by Wolters Kluwer Health in Journal of the American Heart Association
- Vol. 13 (21) , e036208
Open AccessClinical Features and Outcomes of Pediatric MYH7 ‐Related Dilated Cardiomyopathy
Background: Although genetic variants in MYH7 are the most frequent cause of pediatric genetic dilated cardiomyopathy (DCM), there are no studies available describing this entity. We sought to describe clinical features, analyze variant location, and explore predictors of bad prognosis in pediatric MYH7 ‐related DCM. Methods and Results: We evaluated clinical records from 44 patients (24 men; median age at diagnosis, 0.54 [interquartile range, 0.01–10.8] years) with pathogenic/likely pathogenic variants in MYH7 diagnosed with DCM at pediatric age (P =0.002) and LV ejection fraction ≤35% (HR, 4.00 [95% CI, 1.11–14.4]; P =0.03) were the best predictors of bad prognosis. Conclusions: Pediatric MYH7 ‐related DCM is characterized by early onset, frequent LV hypertrabeculation, and poor prognosis. Advanced New York Heart Association class and low LV ejection fraction emerged as predictors of end‐stage heart failure.
- Open Access
- 14 September 2024
- Published by Springer Nature in BMC Cardiovascular Disorders
- Vol. 24 (1) , 1-9
Early surgical outcome for Tetralogy Of Fallot In An African Setting; A Tanzanian experience using retrospective analysis of hospital data
Tetralogy of Fallot (TOF) is typically treated in infancy but often done late in many resource-limited countries, jeopardizing surgical outcomes. This study examined the early results of children undergoing primary complete TOF repair at the Jakaya Kikwete Cardiac Institute (JKCI) in Tanzania, an emerging cardiac center in Eastern Africa. A retrospective cohort study of children ≤ 18 years undergoing primary TOF complete repair between 2019 and 2021 was conducted. Patients with complex TOF and those with obvious genetic syndrome were excluded. Data on socio-demography, pre-and postoperative cardiac complications, Intensive Care Unit (ICU) and hospital stay, and in-hospital and 30-day mortality were analyzed. Logistic regressions were employed to find the factors for mortality, ICU, and hospital stays. The I02 children underwent primary TOF complete repair were majority male (65.7%; n = 67), with a median age of 3.0 years (IQR: 2–6), ranging from 3 months to 17 years.Only 20 patients (19.6%) were below one year of age. Almost all (90%; n = 92) were underweight, with a mean BMI of 14.6 + 3.1 kg/m2 Haematocrits were high, with a median of 48.7 (IQR: 37.4–59.0). The median oxygen saturation was 81% (IQR:72–93). Over a third of patients (38.2%; n = 39) needed Trans annular patch (TAP) during surgery. The median ICU stay was 72 h (IQR:48–120), with ICU duration exceeding three days for most patients. The median hospital stay was 8.5 days (IQR:7–11), with 70 patients (68.2%)experiencing an extended hospital stay of > 7 days. Bacterial sepsis was more common than surgical site infection (5.6%; n = 6 vs. 0.9%;n = 1). No patient needed re-operation for the period of follow up. The in-hospital mortality rate was 5.9%, with no deaths occurring in children less than one year of age nor after discharge during the 30-day follow-up period. No statistically significant differences were observed in outcomes in relation to age, sex, levels of hematocrit and saturations, presence of medical illnesses, and placement of TAP. TOF repairs in this African setting at a national cardiac referral hospital face challenges associated with patients’ older age and compromised nutritional status during the surgery. Perioperative mortality rates and morbidity for patients operated at an older age remain elevated. It’s important to address these issues to improve outcomes in these settings. This study examined the clinical characteristics and 30-day surgical outcomes of patients with Tetralogy of Fallot who were treated in a low-middle-income setting.
- 14 September 2024
- Published by Springer Nature in BMC Cardiovascular Disorders
- Vol. 24 (1) , 1-9
Open AccessEarly surgical outcome for Tetralogy Of Fallot In An African Setting; A Tanzanian experience using retrospective analysis of hospital data
Tetralogy of Fallot (TOF) is typically treated in infancy but often done late in many resource-limited countries, jeopardizing surgical outcomes. This study examined the early results of children undergoing primary complete TOF repair at the Jakaya Kikwete Cardiac Institute (JKCI) in Tanzania, an emerging cardiac center in Eastern Africa. A retrospective cohort study of children ≤ 18 years undergoing primary TOF complete repair between 2019 and 2021 was conducted. Patients with complex TOF and those with obvious genetic syndrome were excluded. Data on socio-demography, pre-and postoperative cardiac complications, Intensive Care Unit (ICU) and hospital stay, and in-hospital and 30-day mortality were analyzed. Logistic regressions were employed to find the factors for mortality, ICU, and hospital stays. The I02 children underwent primary TOF complete repair were majority male (65.7%; n = 67), with a median age of 3.0 years (IQR: 2–6), ranging from 3 months to 17 years.Only 20 patients (19.6%) were below one year of age. Almost all (90%; n = 92) were underweight, with a mean BMI of 14.6 + 3.1 kg/m2 Haematocrits were high, with a median of 48.7 (IQR: 37.4–59.0). The median oxygen saturation was 81% (IQR:72–93). Over a third of patients (38.2%; n = 39) needed Trans annular patch (TAP) during surgery. The median ICU stay was 72 h (IQR:48–120), with ICU duration exceeding three days for most patients. The median hospital stay was 8.5 days (IQR:7–11), with 70 patients (68.2%)experiencing an extended hospital stay of > 7 days. Bacterial sepsis was more common than surgical site infection (5.6%; n = 6 vs. 0.9%;n = 1). No patient needed re-operation for the period of follow up. The in-hospital mortality rate was 5.9%, with no deaths occurring in children less than one year of age nor after discharge during the 30-day follow-up period. No statistically significant differences were observed in outcomes in relation to age, sex, levels of hematocrit and saturations, presence of medical illnesses, and placement of TAP. TOF repairs in this African setting at a national cardiac referral hospital face challenges associated with patients’ older age and compromised nutritional status during the surgery. Perioperative mortality rates and morbidity for patients operated at an older age remain elevated. It’s important to address these issues to improve outcomes in these settings. This study examined the clinical characteristics and 30-day surgical outcomes of patients with Tetralogy of Fallot who were treated in a low-middle-income setting.
- Open Access
- 29 July 2024
- Published by Ubiquity Press, Ltd. in Global Heart
- Vol. 19 (1) , 61
Spectrum of Heart Diseases in Children in a National Cardiac Referral Center Tanzania, Eastern Africa: A Six-Year Overview
Global Heart is the official and primary publication of the World Heart Federation, offering a platform for the dissemination of knowledge on research, developments, trends, solutions and public health programmes in the area of cardiovascular disease. Global Heart welcomes research results, points of view and educational material on the prevention, treatment and control of cardiovascular disease with a special focus on low and middle-income countries which are facing the brunt of epidemiological transition.Global Heart strongly encourages authors to adhere to CONSORT, STROBE, STARD, and PRISMA guidelines for reporting of clinical trials, observational studies, diagnostic test accuracy papers, and systematic reviews or meta-analyses. Authors are required for submission to download and complete the appropriate Equator Network checklist: http://www.equator-network.org/.
- 29 July 2024
- Published by Ubiquity Press, Ltd. in Global Heart
- Vol. 19 (1) , 61
Open AccessSpectrum of Heart Diseases in Children in a National Cardiac Referral Center Tanzania, Eastern Africa: A Six-Year Overview
Global Heart is the official and primary publication of the World Heart Federation, offering a platform for the dissemination of knowledge on research, developments, trends, solutions and public health programmes in the area of cardiovascular disease. Global Heart welcomes research results, points of view and educational material on the prevention, treatment and control of cardiovascular disease with a special focus on low and middle-income countries which are facing the brunt of epidemiological transition.Global Heart strongly encourages authors to adhere to CONSORT, STROBE, STARD, and PRISMA guidelines for reporting of clinical trials, observational studies, diagnostic test accuracy papers, and systematic reviews or meta-analyses. Authors are required for submission to download and complete the appropriate Equator Network checklist: http://www.equator-network.org/.
- Open Access
Diagnostic Accuracy of Physical Examination and Pulse Oximetry for Critical Congenital Cardiac Disease Screening in Newborns
Background: Newborns with a critical congenital heart disease left undiagnosed and untreated have a substantial risk for serious complications and subsequent failure to thrive. Prenatal ultrasound screening is not widely available, nor is postnatal echocardiography. Physical examination is the standard for postnatal screening. Pulse oximetry has been proposed in numerous studies as an alternative screening method. This systematic review and meta-analysis aims to determine the diagnostic accuracies of both screening methods separately and combined. Methods: A systematic literature search of the Embase, PubMed, and Global Health databases up to 30 November 2023 was conducted with the following keywords: critical congenital heart disease, physical examination, clinical scores, pulse oximetry, and echocardiography. The search included all studies conducted in the newborn period using both physical examination and pulse oximetry as screening methods and excluded newborns admitted to the intensive care unit. All studies were assessed for risk of bias and applicability concerns using the QUADAS-2 score. The review adhered to the PRISMA 2020 statement guideline. Results: Out of 2711 articles, 20 articles were selected as eligible for meta-analysis. Cumulatively, the sample included 872,549 screened newborns. The pooled sensitivity of the physical examination screening method was found to be 0.69 (0.66–0.73 (95% CI)) and specificity was found to be 0.98 (0.98–0.98). For the pulse oximetry screening method, the pooled sensitivity and specificity yielded 0.78 (0.75–0.82) and 0.99 (0.99–0.99), respectively. The combined method of screening yielded improved diagnostic characteristics at a sensitivity and specificity of 0.93 (0.91–0.95) and 0.98 (0.98–0.98, respectively. Conclusions: The evidence indicates that combining both physical examination and pulse oximetry to screen for critical congenital heart disease exceeds the accuracy of either separate method. The main limitation is that solely newborns with suspected critical congenital heart disease were subjected to the reference standard. We recommend adapting both methods to screen for critical congenital heart diseases, especially in settings lacking standard fetal ultrasound screening. To increase the sensitivity further, we recommend increasing the screening time window and employing the peripheral perfusion index.
Open AccessDiagnostic Accuracy of Physical Examination and Pulse Oximetry for Critical Congenital Cardiac Disease Screening in Newborns
Background: Newborns with a critical congenital heart disease left undiagnosed and untreated have a substantial risk for serious complications and subsequent failure to thrive. Prenatal ultrasound screening is not widely available, nor is postnatal echocardiography. Physical examination is the standard for postnatal screening. Pulse oximetry has been proposed in numerous studies as an alternative screening method. This systematic review and meta-analysis aims to determine the diagnostic accuracies of both screening methods separately and combined. Methods: A systematic literature search of the Embase, PubMed, and Global Health databases up to 30 November 2023 was conducted with the following keywords: critical congenital heart disease, physical examination, clinical scores, pulse oximetry, and echocardiography. The search included all studies conducted in the newborn period using both physical examination and pulse oximetry as screening methods and excluded newborns admitted to the intensive care unit. All studies were assessed for risk of bias and applicability concerns using the QUADAS-2 score. The review adhered to the PRISMA 2020 statement guideline. Results: Out of 2711 articles, 20 articles were selected as eligible for meta-analysis. Cumulatively, the sample included 872,549 screened newborns. The pooled sensitivity of the physical examination screening method was found to be 0.69 (0.66–0.73 (95% CI)) and specificity was found to be 0.98 (0.98–0.98). For the pulse oximetry screening method, the pooled sensitivity and specificity yielded 0.78 (0.75–0.82) and 0.99 (0.99–0.99), respectively. The combined method of screening yielded improved diagnostic characteristics at a sensitivity and specificity of 0.93 (0.91–0.95) and 0.98 (0.98–0.98, respectively. Conclusions: The evidence indicates that combining both physical examination and pulse oximetry to screen for critical congenital heart disease exceeds the accuracy of either separate method. The main limitation is that solely newborns with suspected critical congenital heart disease were subjected to the reference standard. We recommend adapting both methods to screen for critical congenital heart diseases, especially in settings lacking standard fetal ultrasound screening. To increase the sensitivity further, we recommend increasing the screening time window and employing the peripheral perfusion index.
- Open Access
- 5 November 2022
- Published by Springer Nature in European Journal of Pediatrics
- Vol. 182 (1) , 295-306
Exercise capacity in a cohort of children with congenital heart disease
In patients with congenital heart disease (CHD), reduced exercise capacity can be a predictor for late complications and may be used to guide interventions. Yet, the interpretation of exercise capacity is challenged by changes in body composition during growth. Our aim was to create an overview of disease-specific exercise capacity in children with CHD. We performed a multicentre retrospective study of exercise capacity of CHD patients, aged 6–18 years, tested between January 2001 and October 2018. Sex-specific distribution graphs were made using the LMS method and height to relate to body size. We included all CHD with N > 50, including severe defects (e.g., univentricular heart, tetralogy of Fallot) and “simple” lesions as ventricular septum defect and atrial septum defect. We included 1383 tests of 1208 individual patients for analysis. The peak oxygen uptake (VO2peak, 37.3 ml/min/kg (25th–75th percentile 31.3–43.8)) varied between specific defects; patients with univentricular hearts had lower VO2peak compared with other CHD. All groups had lower VO2peak compared to healthy Dutch children. Males had higher VO2peak, Wpeak and O2pulsepeak than females. Sex- and disease-specific distribution graphs for VO2peak, Wpeak and O2pulsepeak showed increase in variation with increase in height. Conclusion: Disease-specific distribution graphs for exercise capacity in children with CHD from a large multicentre cohort demonstrated varying degrees of reduced VO2peak and Wpeak. The distribution graphs can be used in the structured follow-up of patients with CHD to predict outcome and identify patients at risk. What is Known:• Children with congenital heart disease (COnHD) are at risk to develop heart failure, arrhytmia’s and other complications. Exercise capacity may be an important predictor for outcome in children with ConHD. In children, the interpretation of exercise capacity poses an additional challenge related to physical changes during growth. What is New:• In this report of a multi-center cohort >1300 childrewn with ConHD, we related the changes in exercise capacity to length. We demonstrated that exercise capacity was reduced as compared with healthy children and we observed variation between disease groups. Patients with a univentricular circulation (Fontan) had worse exercise capacity. We constructed disease specific charts of development of exercise capacity throughout childhood, accessible via a web-site. These graphs may help practitioner to guide children with ConHD.
- 5 November 2022
- Published by Springer Nature in European Journal of Pediatrics
- Vol. 182 (1) , 295-306
Open AccessExercise capacity in a cohort of children with congenital heart disease
In patients with congenital heart disease (CHD), reduced exercise capacity can be a predictor for late complications and may be used to guide interventions. Yet, the interpretation of exercise capacity is challenged by changes in body composition during growth. Our aim was to create an overview of disease-specific exercise capacity in children with CHD. We performed a multicentre retrospective study of exercise capacity of CHD patients, aged 6–18 years, tested between January 2001 and October 2018. Sex-specific distribution graphs were made using the LMS method and height to relate to body size. We included all CHD with N > 50, including severe defects (e.g., univentricular heart, tetralogy of Fallot) and “simple” lesions as ventricular septum defect and atrial septum defect. We included 1383 tests of 1208 individual patients for analysis. The peak oxygen uptake (VO2peak, 37.3 ml/min/kg (25th–75th percentile 31.3–43.8)) varied between specific defects; patients with univentricular hearts had lower VO2peak compared with other CHD. All groups had lower VO2peak compared to healthy Dutch children. Males had higher VO2peak, Wpeak and O2pulsepeak than females. Sex- and disease-specific distribution graphs for VO2peak, Wpeak and O2pulsepeak showed increase in variation with increase in height. Conclusion: Disease-specific distribution graphs for exercise capacity in children with CHD from a large multicentre cohort demonstrated varying degrees of reduced VO2peak and Wpeak. The distribution graphs can be used in the structured follow-up of patients with CHD to predict outcome and identify patients at risk. What is Known:• Children with congenital heart disease (COnHD) are at risk to develop heart failure, arrhytmia’s and other complications. Exercise capacity may be an important predictor for outcome in children with ConHD. In children, the interpretation of exercise capacity poses an additional challenge related to physical changes during growth. What is New:• In this report of a multi-center cohort >1300 childrewn with ConHD, we related the changes in exercise capacity to length. We demonstrated that exercise capacity was reduced as compared with healthy children and we observed variation between disease groups. Patients with a univentricular circulation (Fontan) had worse exercise capacity. We constructed disease specific charts of development of exercise capacity throughout childhood, accessible via a web-site. These graphs may help practitioner to guide children with ConHD.